Baking enamel vehicle comprising reaction product of urea,formaldehyde and an oxazoline

ABSTRACT

An improved vehicle for the formulation of baking enamels obtained by reacting an oxazoline with formaldehyde and urea or with an alkylated urea-formaldehyde resin, or with a mixture of urea-formaldehyde resin and dimethylolpropionic acid.

United States Patent [191 Hunsucker Oct. 22, 1974 BAKING ENAMEL VEHICLE COMPRISING [56] References Cited REACTION PRODUCT OF UREA, UNlTED STATES PATENTS FORMALDEHYDE AND AN OXAZOLINE 2,524,112 10/1950 LaPiana et a] 260/67.6 [75] Inventor: Jerry H. Hunsucker, Terre Haute, 3,423349 V1969 Gugliflrdi d 3,464,946 9/1969 Downingm 3,523,123 8/1970 Wehrmeiste [73] Assignee: Commercial Solvents Corporation, 3,654,229 4/1972 Hunsucker zoo/67x Terre Haute, lnd.

I M 1 Primary Examiner-Howard E. Schain [22] Filed ay 21 973 Attorney, Agent, or Firm-Robert H. Dewey; Howard [21] Appl. N0.: 362,594 E p Related U.S. Application Data [60] Continuation-impart of Ser. No. 185,406, Sept. 30, [57] ABSTRACT i971, abandonedv wh ch is a d on of Ser. An improved vehicle for the formulation of baking 361,30, y 1970, PM 1654239 enamels obtained by reacting an oxazoline with formaldehyde and urea or with an alkylated urea- [52] U.S. Cl. 260/70 R, 260/70 A, 260/70 M formaldehyde resin, or i a mixture of ura [51] Int. Cl C08g 9/10, COSg 9/24 f ld h d resin and dimethylolpmpionic acid. [58] Field of Search 260/70 R, 67.5, 70 A 14 Claims, No Drawings BAKING ENAMEL VEHICLE COMPRISING REACTION PRODUCT OF UREA, FORMALDEHYDE AND AN OXAZOLINE CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of copending application Ser. No. 185,406, filed Sept. 30, 1971, now abandoned, which was a division of application Ser. No. 36,680, filed May 12, 1970, now US. Pat. No. 3,654,229, subject matter of which is incorporated herein by reference.

BACKGROUND OF THE lNVENTION This invention relates to an improved vehicle for baking enamels. In a particular aspect, it relates to improved vehicles derived from'oxazolines.

It is known from Purcell, US. Pat. No. 3,248,397, t prepare drying oils from 2-ethenyl oxazolines by co? polymerizing them with olefmic or diolefinic monomers. These drying oils are useful as vehicles in protective coatings and finishes based on them have received wide acceptance. However, the protective coatings industry is ever in need of improvedfinishes, particularly baking enamels intended for use on steel. Particularly desirable are vehicles possessing corrosion resistance,

good adhesion, hardness without loss of flexibility, andrelatively colorless so as not to interfere with pigmenta tion of light-colored finishes. A baking enamel is understood to be a partially polymerized resinous compound, usually dispersed in an organic solvent and formulated with pigments and other additives, which, when applied to a substratum and heated, polymerizes completelyv to form a tough, hard, adherent, flexible protective coating on the substratum.

SUMMARY OF THE INVENTION or (b) an oxazoline corresponding .to formual II:

T R-C CH'zOII with the following Group A: (1) formaldehyde and urea, or (2) alkylated urea-formaldehyde resin, or (3) mixtures of alkylated urea formaldehyde resin and 2,2-dimethylolpropionicacid. R and R are hydrogen or hydroxymethyl; R and R are methyl, ethyl, hydroxymethyl or the group RCH COOCH wherein R is a saturated or unsaturated aliphatic hydrocarbon radical of from 1 to 20 carbon atoms; X is any divalent, or trivalent saturated or unsaturated aliphatic hydrocarbon group of from 1 to 32 carbon atoms; when X-is divalent, a is 2 and b is l, and when X is trivalent, a is 3 and b is 0.

DETAILED DISCUSSION According to the present. invention, there are provided new polymers and resins which, when incorporated in baking enamels, form: hard, flexible, adherent films on a-substratum,:e-.g; metals or textiles, after baking for a suitable period of time at a suitable baking temperature, e.g. about 20minutes at 350F. When the substratum is a textile, e. g.. a natural fiber, a waterproof fabric is obtained.

Generally, the invention contemplatesresinous compounds D obtained by reacting with a member of Group A, an oxazoline compound corresponding to the above formula I. g

These compounds-can be prepared by'reacting them with formaldehyde inabout a 1:2 mole ratio ata temperaturebelow about 125C, according to the method of H. L. Wehrmeister",'U.S. Pat. No. 3,523,123 which isincorporated herein by reference thereto.

The resinous compounds.Dareprepared by reacting an oxazoline corresponding: to formula I:

l. with formaldehyde and urea in a mole ratio of about 1:311 respectively, or

2. with an alkyl'ated urea-formaldehyde resin in a weightratio-of-about 1:1 respectively, or

3. with'the-aforesai'd urea-formaldehyde resin in a weight ratio of about 1:1 in'the presence of dimethylolpropionic acid (DMP-A) in amole ratioof oxazoline to DMPA of about 1:1.

The reaction-for preparingthe resinous compounds D is conducted generally by dissolving the components in a suitable solvent, e.g. butanol, and heating at from about to about C under reflux for about minutes, after which time the solvent and water of reaction are removed by distillation. An acidic catalyst, many of which are known, e.g.,p-tol,uene sulfonic acid, carrbe used when desired. Generally about 0.5 percent ofcatalyst based on the weight of reactants is sufficient.

The above ratios are not critical and-can be varied within rather wide limits without departing from the concepts of the present invention. Generally, however, it is preferred that the amountsof reactants be within about i 20 percent of the ratios setforth.

Compounds E are resinous compounds obtained by reacting with a member of the Group-A compounds an oxazoline corresponding to the above formula [11. These compounds are obtained by reacting with an alkylated urea-formaldehyde resin a bis-oxazoline or a tris-oxazoline obtained by the method. of A. W. Campbell, et al, US. PatNo. 3,419,520, which is incorporated herein by reference thereto. These compounds are derived by reacting an alkanolamine corresponding to formulall:

with a dicarboxylic acid of from-4 to about 36 carbon atoms or with a tri-carboxylic acid of up to about 54 carbon atoms, respectively. R and R can be methyl, ethyl, or hydroxymethyl and can be the same or different. These alkanolamines include-2-amino-2-ethyl-1,3-

propanediol (AEPD), 2-amino-2-methyl-l,3- propanediol (AMPD), 2-amino-2-methyl-l-propanol (AMP), and tris(hydroxymethyl)aminomethane (TA).

There are obtained compounds corresponding to formula III where a is 2 or 3 and b is l or O: i

III

Dicarboxylic acids suitable for preparing the compounds of formula III include, but are not limited to, acids of from 4 to carbon atoms, viz., succiniqglutaric, adipic, pimelic, suberic, azelaic, and sebacic. Also the dimer of C unsaturated fatty acids is a suitable and preferred dicarboxylic acid. Dimerized acids are known to those skilled in the art. They are described in,'for example, Technical Bulletin No. 438C, published by Emery Industries, Inc., Cincinnati, Ohio.

The structure of dimer acid, shown schematically below, is essentially that of a long-chain dicarboxylic acid with two or more alkyl side chains (R and R-,). It ap pears to contain.- at leastone ethylenic bond. Also within the molecule is the linkage at Z resulting from the polymerization of -the two unsaturated fatty acid molecules that form dimer acidvThe exact nature of the linkage is undetermined. It may be as simple as a single carbon-to-carbon bond, or as complex as a cyclicstructure. The total number of carbon atoms is 36.

. .RBY. ime (crux-Liv wuiu coiu Compounds E are prepared by reacting 2. bisoxazoline or a tris-oxazoline corresponding to formula III with an alkylated urea-formaldehyde resin in about a 2:1 weight ratio, when the oxazoline is a trisoxazoline or about 111.2 when the oxazoline is a bisoxazoline, respectively.

The above ratios are not critical and can be varied within rather wide limits without departing from the concepts of the present invention. Generally, however, it is preferred that the amounts of reactants be within about i 20 percent of the ratios set forth.

The formaldehyde used in the present invention can be the 37 or 44 percent by weight aqueous solutions of commerce, or it can be provided by paraformaldehyde. Also suitable are the alcoholic solutions of formaldehyde.

The urea and 2,2-dimethylolpropionic acid used in preparing the compounds of the present invention are commercially available and urea the usual commercial grades are suitable. Urea-formaldehyde suitable for the practice of this invention is commercially available and any of the usual commercial grades are satisfactory for use in the present invention. Alkylated, e.g. butylated or di-butylated urea-formaldehyde, which on heating forms an irreversible resin, is preferred. The methylated or propylated products are also suitable.

The foregoing will be better understood with reference to the following examples. It is understood that the examples are presented for the purpose of illustration only, and it is not intended to be limited thereby.

PREPARATION AND PROPERTIES OF COMPOUNDS D EXAMPLE i The following ingredients were charged to a distillation kettle equipped with a stirrer, a reflux condenser and a take-off head:

Urea (0.5 mole) 30 g Formaldehyde (I2l.5g of 37% solution, 1.5 mole) 45 2-[ l l -Bis(hydroxymethy|)ethyl I-4-ethyl- 4-propionyloxymethyl-Z-oxazolinc (0.5 mole) 136.5

The reactants were mixed and slowly heated to reflux with stirring, (about 35 minutes). The temperature was maintained at reflux (about C) for about 2 hours, then water was separated from the reaction mixture by distillation, resulting in final temperature of about iC as 66 ml of water are removed. The reaction mixture was diluted to 80 percent solids with methanol and the properties of the solution were determined (Table l). A 1.5 mil wet film was drawn down on a steel panel and baked for 20 minutes at 350F, giving a clear film. The properties are given in Table 3.

TABLE 2 PROPERTIES OF BAKED FILMS Example Pencil Reverse Number Hardness* Impact, Lb.

The order of increasing hardness is B. F, HB. H. 3H. 4H, etc.

EXAMPLES 2-3 Following the general procedure of Example I, the oxazoline of Example 1 was used to prepare additional resins. In Examples 2 and 3, the oxazoline was reacted with a butylated-urea resin (Beetle 1032 marketed by American Cyanamid Co.). In Example 3, therewas included 2,2-dimethylolpropionic acid (DMPA) and 0. lg hydrochloride of 2-amino-2-ethyl-l,3-propanediol catalyst. Further details are listed in Table 3. The properties of the resin solutions obtained therefrom are given in Table l. A 1.5 mil wet film was drawn down on steel and baked at 350F for the times shown in Table 3. The baked films were colorless and showed good solvent resistance. Additional properties are given in Table 2.

The experiment of Example 2 is repeated in all essential details except that .0.5 mole of 2-[ 1,1- bis( hydroxymethyl )nonyl -4-methyl-4-hydroxymethyl- 2-oxazoline is substituted 'for the oxazoline of Example 2. The resulting resinous compound has utilityas a vehicle in baking enamels. 1 1

PREPARATION AND PROPERTIES OF COMPOUNDSE EXAMPLE 5 A tris-oxazolinyl compound corresponding to formula III was prepared by mixing 259g, about 0.8 mole, of trimerized fatty acid (Empol 1,040 manufactured by Emery Industries, Inc., was used) with 85.4g, about 0.95 mole, of 2-amino-2-methyl-l-propanol. The mixture was then heated to l70-l75C with stirring until the avid value was 10. Water of reaction was separated in the take-off head. The total reaction time was about 5 hours and the final acid value was 4.9.

A baking enamel was prepared using the following ingredients:

Tris-oxazoline 50g Butylated urea resin 25 Ferricoxide pigment 73.5 Talc 34.8 Calcium carbonate 34.8 Xylene 36.0 p-Tolu'ene sulfonic acid catalyst 0.28 24% Lead drier .48 6% Cobalt drier .48

The above was drawn on a steelpanel and baked at 350F for 20 minutes. The properties are given in Table 2.

EXAMPLE 6 A bis-oxazoline compound corresponding to formula III was prepared by mixing 306g, about 1 mole, of dimerized C fatty acids'with '1 l9g', l mole'of 2-amino-2- ethyll ,3-propanediol,heating to 180-l85C with stirring until the acid value was less than 5. The resulting product had a color, Gardner, of 14, a viscosityat 100 percent'by wt. of 2 and-an acid value of 3.2.

This oxazoline was incorporated into the baking enamel formula, given below, which was'drawn down on standard Q steel panels at 1.5 mil and baked for 20 minutes, 350F, to form in si-tu the resin which acts as the binder in this formulation. The properties of the baked fllm'are given in Table '2.

6% 'Cobalt'drier EXAMPLE 7 A'mixture of mono-oxazoline, bis-oxazoline and trisoxazoline corresponding to formula III were prepared by mixing 153g (0.25 mole) of dim'erized C fatty acid (which consisted of percentof the dimer, 22 percent of the trimer and 3 percent of monobasic acids) with 44.6g (0.5 mole) of Z-aminQ-Z-methyI-I-propanol.

The reactants were mixed in a flask equipped with stirrer, thermometer and nitrogen sparge. The temperatu're was raised to ll'85C and maintained until the acid value was less than 10. The resulting oxazoline mixture was incorporated into the baking enamel formula given below, which was then sprayed on a standard 0 steel panel at 1.5 mil thickness and baked at 350F for 20 minutes to form in situ the resin which acts as the binder in this formulation. The properties of the baked film are given in Table 2.

EXAMPLE 8 A tris-oxazoline corresponding to formula V was prepared by mixing 119.1 g (l-mole) of Z-amino-Z-ethyl- 1,3-propanedil with 259.3g of trimerized C fatty acids (about 0.78 mole) and heating to l80-l85C until the acid number was less than 5. The resulting product had a color of 8 and a viscosity, lOO percent Of 20-27. I

The tris-oxazoline was incorporated into the following formula and drawn down on a standard Q panel at 1.5 mil thickness. The panel was then baked to form the in situ polymer which acts as the binder for this formulations. The properties of the baked film are given in Table 2.

Tris-oxazoline 1.3g Butylated urea resin 70.2 Ferric oxide 73.5 Calcium carbonate 34.8 Talc 34.8 Xylene 36.0

p-Toluene sulfonic acid 014 24% Lead drier .48

v 6% Cobalt drier .48

l claim:

I. A resinous compound consisting of the condensation product of (a) an oxazoline compound corresponding to the formula wherein is a saturated or unsaturated hydrocarbon radical of from l to carbon atoms or (b) an oxazoline corresponding to the formula H1CO wherein X is any divalent, or trivalent saturated or unsaturated aliphatic hydrocarbon group of from 1 to 32 carbon atoms; R and R are hydroxymethyl; R and R are methyl. ethyl. hydroxymethyl or the group R(ll,("(l( ("l*l.; wherein R is a saturated or unsatumtctl aliphatic hydrocarbon radical otIfrom-l to 20 carbon atoms; when X is divalent, a is 2 and b is l, and when X is trivalent, a is.3 and b is O, with (l) formaldehyde and urea, or (2) alkylated. urea-formaldehyde resin, or (3) mixtures of alkylated'urea-formaldehyde resin and 2,2-dimethylolpropionic acid.

2. A resinous compound consisting of the condensation product of an oxazoline compound corresponding to the formula H1 wherein R is a saturated or unsaturated hydrocarbon radical of from 1 to 20 carbon atoms; R and R are methyl, ethyl, hydroxymethyl or the acyloxymethyl group RCH COOCl-l with (1) formaldehyde and urea or (2) an alkylated urea-formaldehyde resin, or ('3) an alkylated urea-formaldehyde resin and 2,2-dimethylolpropionic acid.

3. The compounds of claim 2 wherein R and R of said oxazoline compounds are methyl groups.

4. The compounds of claim 2 wherein R and R of said oxazoline compound are hydroxymethyl groups.

"5. The compounds of claim 2 wherein R and R of said oxazoline compound are represented by the for mula RCH COOCH v '6. The compounds of claim 2 wherein R is of said oxazoline compound methyl or ethyl and R is represented by the formula RCH COOCl-l 7. The resinous compounds of claim 2 obtained by condensing the said oxazoline compound with formaldehyde and urea.

8. The resinous compounds of claim 2 obtained by condensing the said oxazoline compound with a butylated urea-formaldehyde resin.

9.-The resinous compounds of claim 2 obtained by condensing the said oxazoline compound with a butylated urea-formaldehyde resin and 2,2-dimethylolpropionic acid.

10. A resinous compound consisting of the condensation product of an alkylated urea-formaldehyde resin, with an oxazoline compound corresponding to the for l His/i. J.

wherein R and R are hydroxymethyl; R and R are methyl, ethyl, hydroxymethyl or the group RCH COOCH wherein R is a saturated or unsaturated aliphatic hydrocarbon radical of from 1 to 20 carbon atoms; X is any divalent, or trivalent saturated or unsaturated aliphatic hydrocarbon of from i to 32 carbon atoms; when X is divalent, a is 2, and b is l, and when X is trivalent, a is 3, and b is O.

11. The compounds of claim 10 wherein R and R of said oxazoline compound are methyl groups.

12. The compounds of claim l0 wherein R and R of said oxazoline compound are hydroxymethyl groups.

13. The compounds of claim 10 wherein X is divalent.

14. The compounds of claim 10 wherein X is triva- UNITED STATES PATENT OFFICE CERTIFECATE OF CORRECTION Q Patent No. 3,843,607 Dated October 22, 1974 Inventor(s) Jerry H. Hunsucker It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, the formula at lies 62 and following should appear as follows:

HO C (c11 W\ (CH co H 8 2 7 Q (3 CO2H J Column 5, line 63, "avid" should read -acid-- Signed and Sealed this thirteenth Day of April 1976 [SEAL] Q Arrest:

RUTH C. MASON c. MARSHALL DANN Arresting ()jfizer Commissioner nj'lau'ms and Trademarks Q 

1. A RESINOUS COMPOUND CONSISTING OF THE CONDENSATION PRODUCT OF (A) AN OXAZOLINE COMPOUND CORRESPONDING TO THE FORMULA
 2. A resinous compound consisting of the condensation product of an oxazoline compound corresponding to the formula
 3. The compounds of claim 2 wherein R3 and R4 of said oxazoline compounds are methyl groups.
 4. The compounds of claim 2 wherein R3 and R4 of said oxazoline compound are hydroxymethyl groups.
 5. The compounds of claim 2 wherein R3 and R4 of said oxazoline compound are represented by the formula RCH2COOCH2-.
 6. The compounds of claim 2 wherein R3 is of said oxazoline compound methyl or ethyl and R4 is represented by the formula RCH2COOCH2-.
 7. The resinous compounds of claim 2 obtained by condensing the said oxazoline compound with formaldehyde and urea.
 8. The resinous compounds of claim 2 obtained by condensing the said oxazoline compound with a butylated urea-formaldehyde resin.
 9. The resinous compounds of claim 2 obtained by condensing the said oxazoline compound with a butylated urea-formaldehyde resin and 2,2-dimethylolpropionic acid.
 10. A resinous compound consisting of the condensation product of an alkylated urea-formaldehyde resin, with an oxazoline compound corresponding to the formula
 11. The compounds of claim 10 wherein R3 and R4 of said oxazoline compound are methyl groups.
 12. The compounds of claim 10 wherein R3 and R4 of said oxazoline compound are hydroxymethyl groups.
 13. The compounds of claim 10 wherein X is divalent.
 14. The compounds of claim 10 wherein X is trivalent. 